【Python】月の初日や最終日を取得する方法 - Qiita

from datetime import datetime from dateutil.relativedelta import relativedelta today = datetime.now().date() print(today) # => 2020-05-27 last_month_start = (today - relativedelta(months=1)).replace(day=1) print(last_month_start) # => 2020-04-01 last_month_end = today.replace(day=1) - relativedelta(days=1) print(last_month_end) # => 2020-04-30